Rev Diabet Stud, 2017, 14(2-3):260-268 DOI 10.1900/RDS.2017.14.260

The Effects of Vitamin D Supplementation in Newly Diagnosed Type 1 Diabetes Patients: Systematic Review of Randomized Controlled Trials

Elina Gregoriou1, Ioannis Mamais2, Irene Tzanetakou3, Giagkos Lavranos4, Stavri Chrysostomou5

1Department of Life Sciences, European University Cyprus, Engomi, 1516 Nicosia-Cyprus
2Department of Hygiene, Epidemiology and Medical Statistics, Medical School, National and Kapodistrian University of Athens, Greece
3Department of Life Sciences, European University of Cyprus, Nicosia, Cyprus, Engomi, 1516 Nicosia-Cyprus
4Department of Health Sciences, European University Cyprus, Engomi, 1516 Nicosia-Cyprus
5Department of Life Sciences, School of Science, European University Cyprus, Engomi, 1516 Nicosia-Cyprus
Address correspondence to: Stavri Chrysostomou, Department of Life Sciences, School of Science, European University Cyprus, Diogenis Str. 6, Engomi, P.O. Box 22006, 1516 Nicosia-Cyprus, e-mail:


AIM: The aim of this study was to examine the effects of vitamin D supplementation in patients newly diagnosed with type 1 diabetes (T1D) assessed by insulin needs and changes in glycemic indices, as evidenced by randomized controlled trials (RCTs). METHODS: A total of 7 RCTs were retrieved from PubMed/Medline and EBSCO databases by MeSH term search, and were reviewed systematically. The RCTs included examined the effects of alphacalcidole (n = 2), cholecalciferol (n = 2), and calcitriol (n = 3) supplementation on changes in daily insulin dose (DID), fasting Cpeptide (FCP), stimulated C-peptide (SCP), and HbA1c. In total, 287 individuals, diagnosed with T1D within a period of 4 weeks to 1 year and aged between 5 to 38 years, were examined. RESULTS: Significant positive effects on DID, FCP, and SCP levels were observed after supplementation with alphacalcidole and cholecalciferol, whereas supplementation with calcitriol showed no effect. CONCLUSIONS: Vitamin D supplementation in the form of alphacalcidole and cholecalciferol appears to be beneficial in the treatment of T1D patients by attenuating the natural history of the disease.

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Rev Diabet Stud, 2017, 14(2-3):269-278 DOI 10.1900/RDS.2017.14.269

The Role of Iron in Type 1 Diabetes Etiology: A Systematic Review of New Evidence on a Long-Standing Mystery

Karen L. Søgaard1, Christina Ellervik2,3,4,5, Jannet Svensson1,3, Steffen U. Thorsen1

1Copenhagen Diabetes Research Center (CPH-DIRECT), Department of Paediatrics, Herlev Hospital, University of Copenhagen, Herlev Ringvej 75, 2730 Herlev, Denmark
2Department of Production, Research, and Innovation; Region Zealand, Alleen 15, 4180 Sorø, Denmark
3Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
4Department of Laboratory Medicine, Boston Children`s Hospital, 300 Longwood Avenue, 02115, Boston, MA, USA
5Harvard Medical School, 25 Shattuck St, 02115, Boston, MA, USA
Address correspondence to: Karen L. Søgaard, e-mail:


BACKGROUND: The incidence of type 1 diabetes (T1D) is rising, which might be due to the influence of environmental factors. Biological and epidemiological evidence has shown that excess iron is associated with beta-cell damage and impaired insulin secretion. AIM: In this review, our aim was to assess the association between iron and the risk of T1D. METHODS: A systematic literature search was performed in PubMed and EMBASE in July 2016. Studies investigating the effect of iron status/intake on the risk of developing T1D later were included, and study quality was evaluated. The results have been summarized in narrative form. RESULTS: From a total of 931 studies screened, we included 4 observational studies evaluating iron intake from drinking water or food during early life and the risk of T1D. The quality of the studies was moderate to high assessed via the nine-star Newcastle Ottawa Scale. One out of the four studies included in this review found estimates of dietary iron intake to be associated with risk of T1D development, whereas three studies found no such relationship for estimates of iron in drinking water. CONCLUSIONS: The limited number of studies included found dietary iron, but not iron in drinking water, to be associated with risk of T1D. Further studies are needed to clarify the association between iron and risk of T1D, especially studies including measurements of body iron status.

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